In this paper, the morphology of discontinuous precipitates at the grain boundary of Cu-2.0wt% Be alloy and the relationship between the discontinuous precipitates and heat treatment parameters were studied. The heat treatment parameters were selected by orthogonal experimental design, and the samples with a large difference in microstructure were prepared. The discontinuous precipitates mainly exist at the grain boundary and are mainly composed of γ phase and α matrix phase. According to the results of range analysis, the main heat treatment parameters affecting grain boundary reaction amount are secondary aging temperature, followed by primary aging time and secondary aging time. The analysis of anelastic behavior shows that the grain boundary reaction amount has a great influence on the deformation of the sample during loading. This is due to the non coherent relationship between the γ phase formed by discontinuous precipitation and the matrix. There is a disordered region around the γ phase, where the annihilation of dislocations causes the rearrangement of atoms, resulting in crystal slip and plastic deformation of the alloy. However, the two sides of the grain boundary without boundary reactants are crisscrossed with γ "phase, where dislocations are easy to pile up and hinder the crystal sliding.